Differences between class block and function block in python

Question

Code 1 ``` x = 0 class Foo: print(x) x = 1 print(x) print(x) ``` Result 1 ``` 0 1 0 ``` Code 2 ``` x = 0 def foo(): print(x) x = 1 print(x) foo() ``` Result 2 ``` UnboundLocalError: local variable 'x' referenced before assignment. ``` Why can `x` reference objects from two namespaces in `class block`? I don't understand why `Code 1` not throw an `UnboundLocalError`. Inconsistency between function and class bother me. Update: After reading the Python Docs several times, I still cannot understand the scoping rules. The following are blocks: a module, a function body, and a class definition. ...[skip]... If a name is bound in a block, it is a local variable of that block, unless declared as nonlocal. If a name is bound at the module level, it is a global variable. (The variables of the module code block are local and global.) If a variable is used in a code block but not defined there, it is a free variable. If a name binding operation occurs anywhere within a code block, all uses of the…

Accepted Answer

```
x = 0

class Foo:
    print(x)   # Foo.x isn't defined yet, so this is the global x
    x = 1      # This is referring to Foo.x
    print(x)   # So is this

print(x)
```

```
x = 0

def foo():
    print(x)   # Even though x is not defined yet, it's known to be local
               # because of the assignment
    x = 1      # This assignment means x is local for the whole function
    print(x)

foo()
```

Differences between class block and function block in python

Solution

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